Virtual fence

ABSTRACT

The present invention is directed to a virtual fence provided using a plurality of video cameras. A method for providing a virtual fence in accordance with an embodiment includes: positioning a plurality of video cameras about a perimeter to be monitored, the perimeter comprising a plurality of designated areas; for each of the designated areas: capturing video data of the designated area using at least one video camera; analyzing the captured video data to detect an event; and sending at least one of image or video data to a central facility only in response to the detection of the event.

FIELD OF THE INVENTION

The present invention relates to imaging systems, and more specificallyrelates to a virtual fence provided using a plurality of video cameras.

BACKGROUND OF THE INVENTION

Traditional solutions for monitoring a large perimeter using videosurveillance systems and/or the like requires the monitoring of a largenumber of images feeds. Continuous monitoring of each of the image feedstypically requires numerous personnel, which can be cost prohibitive. Toreduce cost, a person may be required to simultaneously monitor a largenumber of image feeds, making it easier for a person to cross theperimeter undetected. In some cases, a sequence of image feeds, eachfrom a different camera, can be displayed. Again, however, this makes itmuch easier for a person to cross the perimeter undetected.

Accordingly, there is a need for a solution that addresses these andother deficiencies of the related art.

SUMMARY OF THE INVENTION

The present invention relates to a virtual fence provided using aplurality of video cameras.

A first aspect is directed to a method for providing a virtual fence,comprising: positioning a plurality of video cameras about a perimeterto be monitored, the perimeter comprising a plurality of designatedareas; for each of the designated areas: capturing video data of thedesignated area using at least one video camera; analyzing the capturedvideo data to detect an event; and sending at least one of an alarm,image data, or video data to a central facility only in response to thedetection of the event.

A second aspect is directed to a virtual fence, comprising: a pluralityof video cameras positioned about a perimeter to be monitored, theperimeter comprising a plurality of designated areas; for each of thedesignated areas: at least one video camera for capturing video data ofthe designated area; a system for analyzing the captured video data todetect an event; and a system for sending at least one of an alarm,image data, or video data to a central facility only in response to thedetection of the event.

A third aspect is directed to a program product stored on a computerreadable medium, which when executed, provides a virtual fence, thecomputer readable medium comprising program code for: capturing videodata using a plurality of video cameras positioned about a perimeter tobe monitored; monitoring the video data using background subtraction todetect an event; and sending at least one of an alarm, image data, orvideo data to a central facility only in response to the detection ofthe event.

A fourth aspect is directed to a method for deploying an application forproviding a virtual fence, comprising: providing a computerinfrastructure being operable to: capture video data using a pluralityof video cameras positioned about a perimeter to be monitored; monitorthe video data using background subtraction to detect an event; and sendat least one of an alarm, image data, or video data to a centralfacility only in response to the detection of the event.

The illustrative aspects of the present invention are designed to solvethe problems herein described and other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present invention will be more readilyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings.

FIG. 1 depicts an illustrative system for providing a virtual fence inaccordance with an embodiment of the present invention.

FIGS. 2A and 2B depict an example of the coverage that can be providedby a pair of video cameras of the virtual fence of FIG. 1 in accordancewith an embodiment of the present invention.

FIG. 3 depicts a flow diagram of an illustrative process for providing avirtual fence in accordance with an embodiment of the present invention.

FIG. 4 depicts a flow diagram of an operation of a virtual fence inaccordance with an embodiment of the present invention.

FIG. 5 depicts an illustrative environment for implementingembodiment(s) of the present invention.

The drawings are merely schematic representations, not intended toportray specific parameters of the invention. The drawings are intendedto depict only typical embodiments of the invention, and thereforeshould not be considered as limiting the scope of the invention. In thedrawings, like numbering represents like elements.

DETAILED DESCRIPTION OF THE INVENTION

As detailed above, the disclosure relates to a virtual fence providedusing a plurality of video cameras.

FIG. 1 depicts an illustrative system 10 for providing a virtual fence12 using a plurality of video cameras 14 in accordance with anembodiment of the present invention. The system 10 employs a computervision technique called background subtraction (BGS) in a novel fashionto create the virtual fence 12. BGS is used to identify moving objectsin a video image that differ significantly from a background. Ingeneral, BGS compares a current video image against a reference image ofa stationary environment to detect regions of change. Such differencesgenerally correspond to moving foreground objects of interest. Anysuitable now known or later developed BGS technique can be used in thepractice of the present invention. In accordance with the presentinvention, BGS is also intended to cover the case where the referencecomparison frame is simply the previous video frame (i.e., framedifferencing). Although described in association with BGS, it will beapparent that other event detection (e.g., moving object detection)techniques can also be used in the practice of the present invention.

The system 10 comprises a series of poles 16. Each pole 16 includes atleast one video camera 14, directed toward a next (or previous) pole 16,and a processing unit 18. Each video camera 14 is mounted on a pole 16such that a next (or previous) pole 16 is within a field of view of thevideo camera 14. In the present invention, a pole 16 comprises any typeof supporting structure (e.g., telephone pole) capable of supporting atleast one video camera 14.

The video camera(s) 14 and processing unit 18 on each pole 16 arecoupled via a communication link 20 to a central facility 22. Theprocessing unit 18 can be mounted to the pole 16, can be buried in theground near the pole 16, or positioned in any suitable location. Inanother embodiment, the processing unit 18 is not co-located with thevideo camera(s) 14 and/or pole 16. For example, the processing unit 18can be provided at a remote location (e.g., at the central facility 22)that is in communication with the video camera(s) 14.

The system 10 is configured to use BGS in a narrow strip 24 between eachpair of poles 16, on at least one side of a line between the poles 16.The series of poles 16 can be arranged in a line (e.g., such as on theborder between two countries, on a bridge, etc.), in a circle (e.g.,around a building, structure, airfield, etc.), and/or in any desiredarrangement.

The video from each video camera 14 on a pole 16 is provided to theprocessing unit 18 on (or associated with) the pole 16, whichcontinuously performs BGS (or other suitable moving object detection) onthe video data. Real ground size estimates can be computed by theprocessing unit 18 to prevent triggering on objects (e.g., animals)smaller than a predetermined size, while still detecting humans. When anevent (e.g., object, motion, motion in a particular direction, and/orother preset conditions) is detected via BGS, the relevant processingunit(s) 18 signals the central facility 22 (e.g., an alarm signal)and/or transmits a still image, live video, and/or a video clip capturedby the relevant video camera(s) 14 to the central facility 22. Theprocessing unit 18 can also detect when the track of an object crosses aspecified line segment (in any direction and/or in one or more specifieddirections (e.g., left-to-right, right-to-left, etc)) rather than (or inaddition to) when an object itself interrupts the line segment. Suchtracking can be provided by the processing unit 18 by linking eachobject detected in one image frame to the corresponding object detectedin a second image frame, thereby generating a motion track connectingthe object positions. This provides for the detection of objects thatmove rapidly relative to the frame rate of the video camera(s) 14 (e.g.,that appear to jump form the left of the fence to the right).

The communication link 20 for transmitting video, images, and/or otherdata, to the central facility 22 can comprise a fiber optic line, awireless data link, and/or the like. The communication link 20 can alsobe used to transmit data from the central facility 22 to each processingunit 18. Power can be supplied to the video camera(s) 14 and theprocessing unit 18 on each pole 16 using copper wires (not shown), via asolar panel affixed to the each pole 16, and/or using any othersolution.

One technique for providing real ground size estimates is to assume aflat ground plane. The lowest point of a detected object is assumed tobe indicative of its position on the ground. Trigonometric relationsconcerning the height, downward tip, focal length, etc., of the videocamera(s) 14, and the pixel height of the detected object can then beused to estimate the real world size of the detected object.

The system 10 places more autonomy at the video cameras 14 (andassociated processing units 18) than conventional video surveillancesystems. Transmission of alarm signals, video, images, and/or other datato the central facility 22 takes place only when it is determined thatan event has occurred. This can reduce cabling and network bandwidthrequirements as well as the physical size and power consumption of thecentral facility 22.

In an illustrative implementation, the video cameras 14 on twoconsecutive poles 16 start ground coverage less than 50% of the way outfrom their respective poles 16, such that there is an overlap ofcoverage. For instance, as depicted in FIG. 2A, the video camera 14A onthe pole 16A is directed toward the pole 16B and starts its coverage ata point P1 that is about 40% of the way out from the pole 16A.Similarly, as depicted in FIG. 2B, the video camera 14B on the pole 16Bis directed toward the pole 16A and starts its coverage at a point P2that is about 40% of the way out from the pole 16B. This gives an objectsize change factor of 2.5×, and there is a 20% overlap region R betweenthe poles 16A, 16B that is monitored by both of the video cameras 14A,14B.

The ground coverage of the video cameras 14A, 14B can start at otherpoints relative to the respective poles 16A, 16B. For example, point P1can be about 30% of the way out from the pole 16A, and point P2 can beabout 30% of the way out from the pole 16B, thereby providing a 40%overlap region R between the poles 16A, 16B. Further, P1 and P2 need notbe the same for each of the video cameras 14A, 14B. For instance, pointP1 can be about 30% of the way out from the pole 16A, while point P2 canbe about 40% of the way out from the pole 16B, thereby providing a 30%overlap region R between the poles 16A, 16B. The spacing of the poles16A, 16B can also be adjusted to vary to size of the overlap region R.For example, the spacing of the poles 16A, 16B can be reduced to provideup to a 100% overlap region R, thus allowing one of the video cameras14A, 14B to fail without any compromise in the detection ability of thevirtual fence 12. Although not optimal in terms of ground coverage andeffectiveness, the video cameras 14A, 14B, and poles 16A, 16B can beconfigured such that there is no overlap region R between the poles 16A,16B.

The spacing between the poles 16 can be governed, for example, by thesmallest object that is to be detected and the focal length of the videocamera 14, among other factors. For night operation in very darkenvironments (e.g., in the desert), the spacing of the poles 16 can belimited by the effective range of the illumination that can be provided.

An illustrative spacing can be about 450 feet (150 yards), which callsfor twelve poles 16 and a total of twenty-four video cameras 14 permile. Using, for example, a video camera 14 having a 50 mm lens with a ⅓inch imager of about 6.4 mm×4.8 mm, this provides a coverage of 58×43feet at 450 feet. This means that one pixel is about 1 inch square, so ahuman would show up as 8 to 16 pixels wide (in VGA resolution). A lowerresolution would also be sufficient (e.g., 2″ pixels).

Assuming a mounting height of 20 feet for each video camera 14, thevideo camera 14 would require a field of view of 6.35 degrees to coverthe full 20 feet of height at a standoff range of 180 feet (i.e., 450feet×40%), which falls within the 7.32 degree horizontal field of viewprovided by a 50 mm lens.

Assuming a video processing speed of 30 fps, even relatively fastobjects (and/or the track thereof) can be detected. For instance, assumea motorcycle is traveling at 120 mph halfway between a pair of the poles16. Using the geometry and imaging parameters postulated above, at thisposition the width of the imaged area is only 22 feet. Since themotorcycle is going 176 feet-per-second, it will cross the imaged areain about ⅛ of a second. To this extent, there will be at least 4 framescontaining the motorcycle, thereby allowing its track to be detected.

FIG. 3 depicts a flow diagram of an illustrative process for providing avirtual fence in accordance with an embodiment of the present invention.

At A1, the perimeter of the virtual fence is defined. At A2, the numberand spacing of poles, configuration of video cameras, processingrequirements, power requirements, etc., required to provide a desiredcoverage are determined. At A3, the poles, video cameras, processingunits, etc. are installed and a communication link to a central facilityis established. At A4, the perimeter established in A1 is monitored forevents using the video data captured by the video cameras, which isanalyzed using BGS by the respective processing units.

FIG. 4 depicts a flow diagram of an operation of a virtual fence inaccordance with an embodiment of the present invention. In B1, eachvideo camera captures video data of its designated area of the perimeterof the virtual fence, and the captured video data is analyzed by arespective processing unit. This continues (NO, B2), until an event isdetected (YES, B2). If an event is detected (YES, B2), the processingunit that detected the event transmits an alarm and/or video/image datafrom the relevant video camera to a central facility in B3. To thisextent, the alarm and/or video/image data is transmitted to the centralfacility only in response to the detection of an event. Flow then passesback to B2, where the monitoring of the perimeter of the virtual fencecontinues.

FIG. 5 shows an illustrative environment 100 for providing at least aportion of a virtual fence in accordance with any/all embodiments of thedisclosure. To this extent, environment 100 includes a computer system102 that can perform the processes described herein (e.g., the computersystem 102 can be configured to perform the functions of the processingunit 18 (FIG. 1). For example, the computer system 102 can be configuredto include a video camera program 104 for controlling the operation of aplurality of video cameras 14 (e.g., a pair of video cameras 14 on apole 16) to obtain video data 106, a monitoring program 108 foranalyzing the video data 106 in order to detect event(s) 110 (e.g.,using BGS), and a reporting program 112 for transmitting an alarm and/orvideo/image data 114 to a central facility 22 in response to thedetection of an event 110, by performing the processes described herein.

The computer system 102 is shown including a processing component 118(e.g., one or more processors), a storage component 120 (e.g., a storagehierarchy), an input/output (I/O) component 122 (e.g., one or more I/Ointerfaces and/or devices), and a communications pathway 124. Ingeneral, the processing component 118 executes program code, such asvideo camera program 104, monitoring program 108, and reporting program112, which are at least partially stored in storage component 120. Whileexecuting program code, the processing component 118 can read and/orwrite data to/from the storage component 120 and/or the I/O component122. The communication pathway 124 provides a communications linkbetween each of the components in computer system 102. The I/O component122 can comprise one or more human I/O devices, which enable a humanuser 126 to interact with the computer system 102, and/or one or morecommunications devices to enable other computer system(s) to communicatewith the computer system 102 using any type of communications link.

The computer system 102 can comprise one or more general purposecomputing articles of manufacture (e.g., computing devices) capable ofexecuting program code installed thereon. As used herein, it isunderstood that “program code” means any collection of instructions, inany language, code or notation, that cause a computing device having aninformation processing capability to perform a particular action eitherdirectly or after any combination of the following: (a) conversion toanother language, code or notation; (b) reproduction in a differentmaterial form; and/or (c) decompression. To this extent, the videocamera program 104, monitoring program 108, and/or reporting program 112can be embodied as any combination of system software and/or applicationsoftware. Further, the video camera program 104, monitoring program 108,and/or reporting program 112 can be implemented using a set of modules128. In this case, a module 128 can comprise a component that performs aset of actions used by the video camera program 104, monitoring program108, and/or reporting program 112. Further, it is understood that someof the actions discussed herein may not be implemented or additionalactions may be implemented by computer system 102.

When the computer system 102 comprises multiple computing devices, eachcomputing device can have only a portion of video camera program 104,monitoring program 108, and/or reporting program 112 installed thereon(e.g., one or more modules 128). However, it is understood that thecomputer system 102 is only representative of various possibleequivalent computer systems that may implement the process describedherein. To this extent, in other embodiments, the actions implemented bythe computer system 102 can be at least partially implemented by one ormore computing devices that include any combination of general and/orspecific purpose hardware and/or program code. In each embodiment, theprogram code and hardware can be provided using standard programming andengineering techniques, respectively.

When the computer system 102 includes multiple computing devices, thecomputing devices can communicate over any type of communications link.Further, while performing the process described herein, the computersystem 102 can communicate with one or more other computer systems usingany type of communications link. In either case, the communications linkcan comprise any combination of various types of wired and/or wirelesslinks; comprise any combination of one or more types of networks; and/orutilize any combination of various types of transmission techniques andprotocols.

It is understood that each of the process flows shown and describedherein is only illustrative. To this extent, numerous variations ofthese process flows are possible, and are included within the scope ofthis disclosure. Illustrative variations include performing one or moreprocesses in parallel and/or a different order, performing additionalprocesses, not performing some processes, and/or the like. To thisextent, the computer system 102, video camera program 104, monitoringprogram 108, and/or reporting program 112 can utilize multipletasks/threads/processes to perform the actions of the processesdescribed herein.

It is further understood that aspects of the invention further providevarious alternative embodiments. For example, in one embodiment, theinvention provides a computer program stored on at least onecomputer-readable medium, which when executed, enables a computer systemto perform the processes described above. To this extent, thecomputer-readable medium can include program code, such as the videocamera program 104, monitoring program 108, and/or reporting program112, which implement some or all of the process described herein. It isunderstood that the term “computer-readable medium” comprises one ormore of any type of tangible medium of expression capable of embodying acopy of the program code (e.g., a physical embodiment). For example, thecomputer-readable medium can comprise: one or more portable storagearticles of manufacture; one or more memory/storage components of acomputing device; a modulated data signal having one or more of itscharacteristics set and/or changed in such a manner as to encodeinformation in the signal; paper; and/or the like.

In another embodiment, a computer system, such as the computer system102, can be obtained (e.g., provided, created, maintained, madeavailable, etc.) and one or more programs/systems for performing theprocess described herein can be obtained (e.g., provided, created,purchased, used, modified, etc.) and deployed to the computer system. Tothis extent, the deployment can comprise one or more of: (1) installingprogram code on a computing device from a computer-readable medium; (2)adding one or more computing devices to the computer system; and (3)incorporating and/or modifying the computer system to enable it toperform the process described herein.

Aspects of the invention can be also implemented as part of a businessmethod that performs the process described herein on a subscription,advertising, and/or fee basis. That is, a service provider could offerto provide some/all of the components/processes needed to provide avirtual fence, as described herein. In this case, the service providercan manage (e.g., create, maintain, support, etc.) some or all of theenvironment 100, such as the computer system 102, that performs theprocess described herein for one or more customers. In return, theservice provider can receive payment from the customer(s) under asubscription and/or fee agreement, receive payment from the sale ofadvertising to one or more third parties, and/or the like.

The foregoing description of the preferred embodiments of this inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed, and obviously, many modifications and variations arepossible.

1. A method for providing a virtual fence, comprising: positioning aplurality of video cameras about a perimeter to be monitored, theperimeter comprising a plurality of designated areas; for each of thedesignated areas: capturing video data of the designated area using atleast one video camera; analyzing the captured video data to detect anevent; and sending at least one of an alarm, image data, or video datato a central facility only in response to the detection of the event. 2.The method of claim 1, wherein analyzing the captured video data todetect an event further comprises: performing moving object detection onthe captured video data.
 3. The method of claim 2, wherein detecting anevent further comprises: detecting when a track of an object crosses thedesignated area.
 4. The method of claim 2, wherein detecting an eventfurther comprises: detecting a size of an object crossing the designatedarea; and limiting the detection of an event to an object having atleast a predetermined size.
 5. The method of claim 1, whereinpositioning a plurality of video cameras further comprises: providing aseries of poles about the perimeter to be monitored, wherein eachdesignated area comprises an area between a respective pair of thepoles; and mounting at least one video camera on each of the poles. 6.The method of claim 5, wherein the video data of each designated area iscaptured by a first video camera mounted on a first of the respectivepair of the poles and a second video camera mounted on a second of therespective pair of the poles.
 7. The method of claim 6, wherein thefirst and second video cameras provide an overlap of coverage in thedesignated area.
 8. The method of claim 5, wherein a pair of videocameras are mounted to each of the poles, further comprising, for eachof the poles: directing a first of the pair of video cameras mounted onthe pole toward a previous pole in the series of poles; and directing asecond of the pair of video cameras mounted on the pole toward a nextpole in the series of poles.
 9. The method of claim 5, furthercomprising: associating a processing unit with each pole for analyzingthe captured video.
 10. A virtual fence, comprising: a plurality ofvideo cameras positioned about a perimeter to be monitored, theperimeter comprising a plurality of designated areas; for each of thedesignated areas: at least one video camera for capturing video data ofthe designated area; a system for analyzing the captured video data todetect an event; and a system for sending at least one of an alarm,image data, or video data to a central facility only in response to thedetection of the event.
 11. The system of claim 10, wherein the systemfor analyzing the captured video data to detect an event furthercomprises: a system for performing moving object detection on thecaptured video data.
 12. The system of claim 11, wherein the system foranalyzing the captured video data to detect an event further comprises:a system for detecting when a track of an object crosses the designatedarea.
 13. The system of claim 11, wherein the system for analyzing thecaptured video data to detect an event further comprises: a system fordetecting a size of an object crossing the designated area; and a systemfor limiting the detection of an event to an object having at least apredetermined size.
 14. The system of claim 10, further comprising: aseries of poles located about the perimeter to be monitored, whereineach designated area comprises an area between a respective pair of thepoles, and wherein at least one video camera is mounted on each of thepoles.
 15. The system of claim 14, wherein the video data of eachdesignated area is captured by a first video camera mounted on a firstof the respective pair of the poles and a second video camera mounted ona second of the respective pair of the poles.
 16. The system of claim15, wherein the first and second video cameras provide an overlap ofcoverage in the designated area.
 17. The system of claim 14, wherein apair of video cameras are mounted to each of the poles, and wherein afirst of the pair of video cameras mounted on the pole is directedtoward a previous pole in the series of poles and a second of the pairof video cameras mounted on the pole is directed toward a next pole inthe series of poles.
 18. The system of claim 14, further comprising: aprocessing unit associated with each pole for analyzing the capturedvideo.
 19. A program product stored on a computer readable medium, whichwhen executed, provides a virtual fence, the computer readable mediumcomprising program code for: capturing video data using a plurality ofvideo cameras positioned about a perimeter to be monitored; monitoringthe video data using background subtraction to detect an event; andsending at least one of an alarm, image data, or video data to a centralfacility only in response to the detection of the event.
 20. A methodfor deploying an application for providing a virtual fence, comprising:providing a computer infrastructure being operable to: capture videodata using a plurality of video cameras positioned about a perimeter tobe monitored; monitor the video data using background subtraction todetect an event; and send at least one of an alarm, image data, or videodata to a central facility only in response to the detection of theevent.